Q&A Hero

Q: The two photosystems of light reactions are designated a. type 1 and type 2. b. type I and type II. c. photosystem A and photosystem B. d. photosystem 680 and photosystem 700. e. photosystem I and photosystem II.

Q: The oxygen released in photosynthesis comes from a. carbon dioxide. b. glucose. c. ribulose bisphosphate. d. water. e. atmospheric oxygen.

Q: Which of the following is not a product of the light-independent reactions? a. ADP. b. NADP+. c. oxygen. d. glucose. e. all these are products.

Q: Actual assembly of sugars during photosynthesis a. occurs during light-independent reactions. b. takes place in the stroma. c. requires NADPH. d. requires ATP. e. does all of these.

Q: Where are sugars formed in the chloroplasts? a. on the outer membrane b. on the inner membrane c. in the thylakoid compartment d. in the stroma e. within the thylakoid membrane

Q: Which of the following statements is TRUE about NADPH? a. It is an enzyme. b. It is the oxidized form of NADP+. c. It is generated n the light-dependent reactions of photosynthesis. d. It accepts hydrogen and electrons from carbohydrates. e. It obtains energy from ATP.

Q: Which of the following is not produced in the light dependent reactions? a. glucose. b. oxygen. c. ATP. d. NADPH. e. all of these are produced.

Q: Where in a plant cell are chloroplasts found? a. on the cell membrane b. in the cytoplasm of the cell c. in the stroma d. in the thylakoids e. none of these

Q: The following questions refer to the figure above illustrating the results from Engelmann's investigation. The best light to grow the alga in is ____, according to the figure. a. blue-violet b. blue-green c. green-yellow d. yellow-orange e. orange-red

Q: The following questions refer to the figure above illustrating the results from Engelmann's investigation. According to the figure, the most effective wavelength for photosynthesis occurs in the algae that are at ____ nanometers. a. 680 b. 700 c. 400 d. 425 e. 550

Q: The following questions refer to the figure above illustrating the results from Engelmann's investigation. Engelmann's experiment was designed to determine a. what wavelengths comprise visible light. b. what colors are contained in visible light. c. if bacteria are attracted to oxygen. d. if photosynthesis releases oxygen. e. none of these.

Q: Which of the following choices is NOT TRUE? a. Carotenoids use yellow and red light to assist in photosynthesis. b. Carotenoids are accessory pigments that capture certain energy from light and transfer it to chlorophyll a. c. The presence of carotenoids in a leaf is masked by the presence of chlorophyll throughout the growing season. d. Carotenoids absorb blue and violet wavelengths and reflect red, orange, and yellow. e. Both carotenoids and anthocyanins reflect red wavelengths.

Q: Which of the following statements is NOT TRUE concerning an electron that has absorbed a photon? a. It moves to a higher energy level. b. It becomes more stable. c. It quickly returns to its original energy level. d. It may emit energy. e. It becomes excited.

Q: A pigment absorbs a photon if the energy of the photon is a. exactly enough to boost an electron of the pigment to a higher energy level. b. slightly more than the energy of the electron absorbing the photon. c. significantly more than the energy of the electron absorbing the photon. d. exactly twice the energy of the electron absorbing the photon. e. any of these, depending on the type of pigment.

Q: Which of the following are accessory pigments in photosynthesis? a. carotenoids b. phycobillins c. anthocyanins d. chlorophyll b e. all of these

Q: Chlorophyll does not absorb which color of light? a. red b. yellow c. orange d. green e. blue

Q: Which of the following statements is(are) generally TRUE of pigments? a. They absorb some photons. b. They reflect all photons. c. They absorb photons of all colors. d. They absorb photons of all wavelengths. e. They do all of these.

Q: Compare and contrast facilitated and active transport?

Q: Discuss the role of turgor in the crisp lettuce purchased at the grocery store looking much limper by the time it gets home.

Q: Describe how the laws of thermodynamics would impact the Earth were the sun's light suddenly blocked?

Q: The enzyme that works in conjunction with ATP to produce bioluminescence is called __________.

Q: The loss of an electron by a molecule is called __________.

Q: Some enzymes are controlled by having nonsubstrates bind to a nonactive site and result in a change in their overall structure; these are called __________.

Q: A chemical interaction in which the products contain less free energy than the reactants is called a(n) __________ reaction.

Q: The items below are processes that occur during different stages of photosynthesis. Answer the following questions by selecting one of these three processes. a. oxidation b. reduction c. phosphorylation This process occurs when an electron transport molecule gives up an electron.

Q: The items below are processes that occur during different stages of photosynthesis. Answer the following questions by selecting one of these three processes. a. oxidation b. reduction c. phosphorylation This process is involved when a photon of light energy causes an electron to leave the chlorophyll molecule.

Q: The items below are processes that occur during different stages of photosynthesis. Answer the following questions by selecting one of these three processes. a. oxidation b. reduction c. phosphorylation This process occurs when an electron is passed to an electron acceptor molecule, such as NADP+.

Q: The items below are processes that occur during different stages of photosynthesis. Answer the following questions by selecting one of these three processes. a. oxidation b. reduction c. phosphorylation This process leads to the formation of ATP from ADP plus inorganic phosphate.

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed phosphorylation

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed feedback inhibition

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed equilibrium

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed entropy

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed catalase

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed catalyst

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed NADP+

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed adenosine triphosphate

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed allosteric enzyme

Q: Choose the one most appropriate answer for each. a. rate of forward reaction about equals rate of reverse reaction b. coenzyme that diffuses freely through the cytoplasm c. attachment of a phosphate group by a high-energy bond d. an excess of end-product molecules alters the shape of the first enzyme in the pathway and shuts off that metabolic pathway e. part of an enzyme that binds to the substrate f. by binding a regulatory molecule, it changes the activity of a metabolic pathway g. affects rates of chemical reactions h. universal energy currency i. assists in the detoxification of ethanol j. a measure of the degree of energy change after a concentrated form of energy has been dispersed active site

Q: During receptor-mediated endocytosis a. plasma membrane receptors bind molecules to be enclosed. b. a small pit forms beneath the receptors. c. a pit closes back on itself. d. a vesicle forms. e. all of these occur.

Q: The action of a white blood cell engulfing a bacterium is a. pinocytosis. b. phagocytosis. c. exocytosis. d. endocytosis. e. phagocytosis and endocytosis.

Q: Which of the following is NOT a form of passive transport? a. osmosis b. facilitated diffusion c. simple diffusion d. exocytosis e. none of these

Q: The method of movement that requires the expenditure of ATP molecules is a. simple diffusion. b. facilitated diffusion. c. osmosis. d. active transport. e. bulk flow.

Q: The rate of diffusion through a selectively permeable membrane will be lowest when which of the following is(are) true? I. Concentration gradients are steep. II. Temperatures are low. III. Solutes are small molecules. a. I only b. II only c. I and III d. II and III e. I, II, and III

Q: Which of the following affects the rate of diffusion through a selectively permeable membrane? I. concentration gradient II. temperature III. molecular size a. I only b. II only c. I and II d. II and III e. I, II, and III

Q: Which statement is NOT true? a. Membranes are often perforated by proteins that extend through both sides of the membrane. b. Some membranes have proteins with channels that allow for the passage of hydrophilic substances. c. Hydrophilic substances have an easier time passing through the lipid bilayer than do hydrophobic substances. d. The current concept of a membrane is best summarized by the fluid mosaic model. e. All of these statements are NOT true.

Q: Which of the following terms best describes the role of certain metal ions and coenzymes in metabolic processes? a. reactants b. intermediates c. cofactors d. products e. catalysts

Q: All of the following are true of the process of phosphorylation EXCEPT that a. a molecule gains a phosphate group. b. a molecule loses a phosphate group. c. molecules become less stable. d. it is used to prime molecules to react. e. it produces ADP from ATP.

Q: A "high-energy bond" in ATP a. absorbs a large amount of free energy when the phosphate group is attached during hydrolysis. b. is formed when ATP is hydrolyzed to ADP and one phosphate group. c. is similar to the bonds in glucose molecules; that is why glucose can be used as a source of metabolic energy. d. contributes to the "energy in" part of an endergonic reaction. e. is/does all of these.

Q: In oxidation-reduction reactions, all of the following are true EXCEPT a. one molecule gives up electrons. b. one molecule gains electrons. c. cells release energy. d. the molecule that accepts electrons is oxidized. e. hydrogen ions are usually released.

Q: Which of the following statements is true of metabolic pathways? a. They are enzyme-mediated sequences of reactions. b. They may be biosynthetic or degradative. c. Photosynthesis is a biosynthetic pathway. d. Catabolism is a degradative pathway. e. All of these statements are true.

Q: In some cases, inhibitors or activators of enzyme-catalyzed reactions act by a. binding to the substrates. b. affecting the supply of ATP. c. reversibly binding to an enzyme's allosteric site. d. reducing or increasing the concentration of enzymes. e. binding to the products.

Q: In the image above, the substance indicated as "A" is a(n) a. inhibitor. b. activator. c. substrate. d. coenzyme. e. cofactor.

Q: In the image above, the substance indicated as "B" is a(n) a. inhibitor. b. activator. c. substrate. d. coenzyme. e. cofactor.

Q: In the image above an enzyme substrate complex is represented by a. C. b. D. c. E. d. D and E. e. None of these.

Q: The figure above represents a. an exergonic reaction. b. a metabolic pathway. c. allosteric inhibition. d. allosteric activation. e. all of these.

Q: Allosteric enzymes a. have regions that bind with inhibitor or activator molecules. b. are associated with important energy-carrying nucleotides. c. are not affected by temperature or pH. d. have two active sites. e. have all of these.

Q: Allosteric inhibition generally results from a. excess substrates. b. binding of regulatory molecules at sites other than the active sites. c. a change in the temperature of the system. d. a lack of coenzymes. e. changes in pH.

Q: Which of the following statements is false? a. Enzymes are highly specific and act on chemicals called substrates. b. Enzymes act as catalysts and speed up chemical reactions within cells. c. Most enzymes work best under very low pH conditions. d. Most enzymes are proteins. e. Enzymes can become deactivated by high fevers.

Q: An enzyme is thought to optimize the fit between substrates by restraining and stretching or squeezing them into certain shapes and moving them to the transition state as described by the ____ model of enzyme activity. a. lock and key b. induced-fit c. template d. activation e. conformational

Q: All of the following are factors in enzyme-catalyzed reactions that work alone or in combination to lower the activation energy EXCEPT a. helping substrates get together. b. orienting substrates in positions favoring reaction. c. breaking the laws of thermodynamics. d. shutting out water molecules. e. inducing a fit between enzyme and substrate.

Q: The active site of an enzyme a. is where the coenzyme is located. b. is a specific bulge or protuberance on an enzyme. c. is a groove or crevice in the structure of the enzyme complementary to the substrate. d. will react with only one substrate no matter how many molecules may resemble the shape of the substrate. e. rigidly resists any alteration of its shape.

Q: Which of the following statements is false? a. Enzymes catalyze reversible reactions in either direction. b. Enzymes are highly specific. c. Most enzymes are carbohydrate molecules. d. Enzymes do not allow some reactions to occur that would never occur without them. e. Enzymes may be temporarily modified during their involvement with the substrate.

Q: Enzymes a. control the speed of a reaction. b. change shapes to facilitate certain reactions. c. may place physical stress on the bonds of the substrate. d. always work on their own. e. do all of these.

Q: Which of the following is NOT true of enzyme behavior? a. Enzyme shape may change during catalysis. b. The active site of an enzyme orients its substrate molecules, thereby promoting interaction of their reactive parts. c. All enzymes have an active site where substrates are temporarily bound. d. Each enzyme can catalyze only a specific reaction. e. Enzyme activity is not affected by pH and temperature.

Q: Which of the following statements about exergonic reactions is false? a. They release energy. b. Glucose metabolism is an example. c. Their products have more energy than the reactants. d. Some energy is converted to less biologically useful forms. e. Bonds are broken.

Q: Endergonic reactions a. result in products with less energy than the reactants. b. require a net input of energy. c. occur in the breakdown of glucose. d. are used by cells to provide energy for biological reactions. e. break down large molecules into smaller molecules.

Q: CO2 and H2O will not form glucose on their own because a. CO2 does not contain sufficient energy. b. H2O does not contain sufficient energy. c. neither CO2 nor H2O contain sufficient energy. d. the concentration of CO2 is too low in the atmosphere. e. the bonds of CO2 and H2O are too stable to be broken without an input of energy.

Q: The activation energy of a reaction refers to the minimum amount of energy a. released by the reaction. b. in the reactants. c. in the products. d. necessary to cause a reaction to proceed on its own. e. difference between the energy of the reactants and the energy of the products.

Q: Which of the following is an application of the first law of thermodynamics? a. The level of entropy increases as time passes. b. Living organisms represent an exception to the laws of energy. c. The quantity of energy does not increase or decrease in the universe. d. Fungi and plants do not make their own energy but derive it from somewhere else. e. The amount of energy found in the compounds on one side of an equation is equal to that on the other side.

Q: Which of the following statements is false? a. The universe has a specific amount of energy. b. One form of energy can be converted to other forms of energy. c. Whenever energy conversions occur, some energy is converted to less concentrated forms. d. Once energy is utilized, it disappears. e. There are differences in the quality of energy.

Q: The second law of thermodynamics states that a. energy can be transformed into matter, and because of this, something is obtained for nothing. b. energy can be destroyed during nuclear reactions such as those that occur inside the sun. c. if energy is gained by one region of the universe, another place in the universe also must gain energy in order to maintain the balance of nature. d. energy tends to flow from concentrated to less concentrated forms. e. none of these is true.

Q: According to the first law of thermodynamics, a. the energy of a system may increase if there is a corresponding decrease in energy elsewhere in the universe. b. the amount of energy in the universe is constant. c. chemical reactions do not create or destroy energy. d. energy can change from one form to another. e. all of these are true.

Q: Energy is commonly defined as "the capacity to do work." This definition is a. incorrect. b. adequate in the physical sciences. c. adequate in the biological sciences. d. a clue to the actual properties of the concept. e. not accepted by most scientists.

Q: The enzyme responsible for breaking down alcohol is a. alcohol methylase. b. alcohol polyphosphorylase. c. hydroxyl alcoholgenase. d. transmethylogenase. e. alcohol dehydrogenase.

Q: Which of the following quantities of alcoholic beverages have the least damaging effect on the liver? a. a bottle of beer b. a glass of wine c. a shot of vodka d. either a bottle of beer or a glass of wine e. all have the same amount of ethanol and therefore have similar effects on the liver

Q: The figure is a photomicrograph ofa. a nucleus.b. a Golgi body.c. endoplasmic reticulum.d. a vacuole.e. a nucleoid.

Q: What are the properties of life?

Q: Chart the path of molecules of a secreted protein beginning at the DNA for a eukaryote.

Q: Prokaryote means before the nucleus, but what general feature could prokaryotes also be said to lack?

Q: In the development of the cell theory, Schleiden and Schwann did not study prokaryotes. Why might this have limited their understanding of cells?